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Nové metody ve schvalování úvěrů
Rychnovský, Michal ; Arlt, Josef (advisor) ; Pecáková, Iva (referee) ; Veselý, Petr (referee)
This thesis contributes to the field of applied statistics and financial modeling by analyzing mathematical models used in retail credit underwriting processes. Specifically, it has three goals. First, the thesis aims to challenge the performance criteria used by established statistical approaches and propose focusing on predictive power instead. Secondly, it compares the analytical leverage of the established and other suggested methods according to the newly proposed criteria. Third, the thesis seeks to develop and specify a new comprehensive profitability-based underwriting model and critically reflect on its strengths and weaknesses. In the first chapter I look into the area of probability of default modeling and argue for comparing the predictive power of the models in time rather than focusing on the random testing sample only, as typically suggested in the scholarly literature. For this purpose I use the concept of survival analysis and the Cox model in particular, and apply it to a real Czech banking data sample alongside the commonly used logistic regression model to compare the results using the Gini coefficient and lift characteristics. The Cox model performs comparably on the randomly chosen validation sample and clearly outperforms the logistic regression approach in the predictive power. In the second chapter, in the area of loss given default modeling I introduce two Cox-based models, and compare their predictive power with the standard approaches using the linear and logistic regression on a real data sample. Based on the modified coefficient of determination, the Cox model shows better predictions. Third chapter focuses on estimating the expected profit as an alternative to the risk estimation itself and building on the probability of default and loss given default models, I construct a comprehensive profitability model for fix-term retail loans underwriting. The model also incorporates various related risk-adjusted revenues and costs, allowing more precise results. Moreover, I propose four measures of profitability, including the risk-adjusted expected internal rate of return and return on equity and simulate the impact of the model on each of the measures. Finally, I discuss some weaknesses of these approaches and solve the problem of finding default or fraud concentrations in the portfolio. For this purpose, I introduce a new statistical measure based on a pre-defined expert critical default rate and compare the GUHA method with the classification tree method on a real data sample. While drawing on the comparison of different methods, this work contributes to the debates about survival analysis models used in financial modeling and profitability models used in credit underwriting.
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Reduced-form approach to LGD modelling
Hlavatá, Ivana ; Seidler, Jakub (advisor) ; Šopov, Boril (referee)
The master thesis deals with the advanced methods for estimating credit risk parameters from market prices: probability of default (PD) and loss given default (LGD). Precise evaluation of these parameters is important not only for banks to calculate their regulatory capital but also for investors to price risky bonds and credit derivatives. We provide forward looking reduced-form analytical method for calculation of PD and LGD of corporate defaultable bonds based on their quoted market prices, prices of equivalent risk-free bonds and quoted credit default swap spreads of the issuer of these bonds. This is reversed to most of the studies on credit risk modeling, as aim is not to price instruments based on estimated credit risk parameters, but to calculate these parameters based on the available market prices. Furthermore, compared to other studies, the LGD parameter is assumed to be endogenous and we provide the method for its simultaneous calculation with the probability of default. Finally, using developed methods, we estimate implied PD and LGD for five European banks assuming that the risk is priced correctly by other investors and the markets are efficient. JEL Classification: C02, C63, G13, G33 Keywords: credit risk, loss given default, probability of default, credit default swap Author's...
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Reduced-form Approach to LGD Modeling
Hlavatá, Ivana ; Seidler, Jakub (advisor) ; Šopov, Boril (referee)
The rigorous thesis deals with the advanced methods for estimating credit risk parameters from market prices: probability of default (PD) and loss given default (LGD). Precise evaluation of these parameters is important not only for banks to calculate their regulatory capital but also for investors to price risky bonds and credit derivatives. We develop two forward looking reduced-form analytical methods for calculation of PD and LGD of corporate defaultable bonds based on their quoted market prices, prices of equivalent risk-free bonds and quoted senior and subordinated credit default swap spreads of the issuer of these bonds. This is reversed to most of the studies on credit risk modeling, as aim is not to price instruments based on estimated credit risk parameters, but to calculate these parameters based on the available market quotes. Furthermore, compared to other studies, the LGD parameter is assumed to be endogenous and we provide the method for its simultaneous calculation with the probability of default. Finally, using developed methods, we estimate implied PD and LGD for nine European banks assuming that the risk is priced correctly by other investors and the markets are efficient. JEL Classification: C02, C63, G13, G33 Keywords: credit risk, loss given default, probability of default,...
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Credit Risk in the Macroprudential Framework: Three Essays
Seidler, Jakub ; Dědek, Oldřich (advisor) ; Witzany, Jiří (referee) ; Komárek, Luboš (referee) ; Schmieder, Christian (referee)
Charles University in Prague Faculty of Social Sciences Institute of Economic Studies Credit Risk in the Macroprudential Framework: Three Essays DISSERTATION Author: PhDr. Jakub Seidler Supervisor: prof. Ing. Oldřich Dědek, CSc Academic Year: 2011/2012 Abstract This thesis focuses on proper credit risk identification with respect to macroprudential policies, which should mitigate systemic risk accumulation and contribute to higher financial stability of the financial sector. The first essay deals with a key credit risk parameter - Loss Given Default (LGD). We illustrate how the LGD can be estimated with the help of an adjusted Mertonian structural approach. We present a derivation of the formula for expected LGD and show its sensitivity analysis with respect to other company structural parameters. Finally, we estimate the five-year expected LGDs for companies listed on Prague Stock Exchange and find that the average LGD for the analyzed sample is around 20-50%. The second essay examines the issue of how to determine whether the observed level of private sector credit is excessive in the context of the "countercyclical capital buffer", a macroprudential tool proposed in the new regulatory framework of Basel III by the Basel Committee on Banking Supervision. An empirical analysis of selected Central and...
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Metrics used in credit risk
Kožár, Ondrej ; Luc, Ladislav (advisor) ; Franěk, Petr (referee)
This thesis focuses on the issue of metrics used in credit risk. Specifically, the capital requirement, the NPL share and risk costs. The first section describes the credit risk and with what metrics can be measured. In this section you can also find out what parameters are required for their intended use, these parameters are the Probability of default, Amortization, Exposure, NPL and the Loss given default . The practical part of this work is devoted to the analysis of the situation in the Česká spořitelna and design solutions to identified problems. From this analysis crystallize two fundamental problems arising from lack of employee familiarity with metrics used in credit risk .For their solution is to use the first part of this paper an overview of metrics with clarifying some key features. The aim of this work was to create a comprehensive list of metrics used in credit risk, an explanation of their interaction and the use of tools to solve the problem situation in the Česká spořitelna.
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Multifactor dynamic credit risk model
Dufek, J. ; Šmíd, Martin
We propose a new dynamic model of the Merton type, based on the Vasicek model. We generalize Vasicek model in three ways: we add model for loss given default (LGD), we add dynamics to the model and we allow non-normal distri- butions of risk factors. Then we add a retrospective interaction of underlying factors and found a non-linear behaviour of these factors. In particular, the evolution of factors underlying the DR and the LGD is assumed to be ruled by a non-linear vector AR process with lagged DR and LGD and their non-linear transformations. We apply our new model on real US mortgage data and demonstrate its statistical significance.
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The merton approach to estimating loss given default: application to the Czech republic
Seidler, Jakub ; Jakubík, Petr
This paper focuses on a key credit risk parameter – Loss Given Default (LGD). Writers illustrate how the LGD can be estimated with the help of an adjusted Mertonian structural approach. They present a derivation of the formula for expected LGD and show its sensitivity analysis with respect to other company structural parameters. Finally, we estimate the five-year expected LGDs for companies listed on Prague Stock Exchange and find that the average LGD for the analyzed sample is around 20–50%.
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Internal rating method as an instrument to value credit risk
Heinzel, Lukáš ; Jablonský, Petr (advisor) ; Prokop, Martin (referee)
This thesis is focused on the internal rating method as an instrument to value the credit risk. Firstly, it is aimed on the general method of measurement and control over the credit risk in banks, then there is introduced a process how to develop Basel regulation. Basel II. agreement, which is the focal point of this thesis, allows banks to use standardized approach or IRB method to evaluate the credit risk. After the definition of the standardized method the author focuses on IRB method. There are introductory IRB notes, then it is concentrated on an approval of using this approach by a regulator. The main part of the thesis is given to the calculation of the capital requirement by IRB method. Descriptions of the general formulas and risk parameters are described there. The calculation is demonstrated by a real illustration.
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